Fraction collecting apparatus

ABSTRACT

Fraction collecting apparatus for receiving the liquid output of a fractionating column and separating the same in proportion to time increments of uniform duration. A disc having a plurality of equi-size openings therein, which openings are spaced uniformly along a spiral path. A carriage having an arm overlying the disc that supports an outlet from the fractionating column. The carriage is moved radially as the disc is rotated so that the arm and the nozzle mounted thereto follow the spiral path. Disc rotation is effected by a drive wheel mounted on the carriage which drives the disc such that the tangential speed of the particular opening aligned with the nozzle is constant, thereby assuring constancy and uniformity of the time increment that each opening in the disc receives liquid from the fractionating column.

United States Patent 91 McNeill [451 Mar. 18, 1975 FRACTION COLLECTING APPARATUS [52] 11.5. C1. 141/130, 23/253 R [51] Int. Cl B65b 43/50 [58] Field of Search... 141/130; 73/4254 R, 423 A;

23/253 R, 259; 274/1 F, 23 A; 353/110 FOREIGN PATENTS OR APPLICATIONS 909,844 11/1962 Great Britain 141/130 325,376 2/1930 Great Britain l4l/l30 Primary Examiner-Richard E. Aegerter Assistant Examiner-John W. Shepperd Attorney, Agent, 0" Firm-Thomas H. Olson [57] ABSTRACT Fraction collecting apparatus for receiving the liquid output of a fractionating column and separating the same in proportion to time increments of uniform duration. A disc having a plurality of equi-size openings therein, which openings are spaced uniformly along a spiral path. A carriage having an arm overlying the disc that supports an outlet from the fractionating column. The carriage is moved radially as the disc is rotated so that the arm and the nozzle mounted thereto follow the spiral path. Disc rotation is effected by a drive wheel mounted on the carriage which drives the disc such that the tangential speed of the particular opening aligned with the nozzle is constant, thereby assuringconstancy and uniformity of the time increment that each opening in the disc receives liquid from the fractionating column.

4 Claims, 6 Drawing Figures 1 FRACTION COLLECTING APPARATUS FIELD OF THE INVENTION in collecting the output; the present invention achieves a a high degree of accuracy with relatively uncomplex apparatus.

DESCRIPTION OF THE PRIOR ART Among the known prior art is U.S. Pat. No. 3,202,325 which serves well in dividing or fractionating the output of analysis equipment into uniform time increments. The patented apparatus achieves uniformity of time increments by providing collection chambers that have different dimensions to the end that the time that each chamber is in receiving relation to the liquid output is constant. The accuracy of the patented apparatus is achieved only by careful attention to the proportioning and fabrication of the collection chambers.

SUMMARY OF THE INVENTION The embodiment of the present invention that is described in more detail hereinafter includes a disc which defines in the upper surface thereof a plurality of equisize openings or chambers which are uniformly spaced along a spiral path on the disc. A base having an upstanding shaft supports the disc for rotation. The base also includes a carriage that is supported beneath the disc on a radially extending path. Mounted on the car riage is a drive wheel which makes frictional engagement with the lower surface of the disc. The drive wheel is motor driven so as to impart rotative motion to the disc. A subassembly is provided for constraining the drive wheel in alignment below the spiral path of the openings. Because the motor that drives the drive wheel operates at a constant speed, and tangential velocity of the portion of the disc in contact with the drive wheel is constant. Also mounted on the carriage is an arm, the upper end of which overlays the upper surface of the disc in vertical alignment with the drive wheel. Thus the tangential speed of the openings passing under the free end of the arm is constant.

For constraining the drive wheel for movement on the spiral path there is a capstan which is part of the disc support shaft and is driven in response to rotation of the disc. A cable or like flexible tension member is fastened to the capstan so as to be wound therearound as the disc rotates. The free end of the cable is operatively connected to the carriage so that the carriage is moved along the radial path in response to rotation of the disc. Accordingly, the point of contact between the drive wheel and the lower surface of the disc follows the same spiral path as the openings or chambers follow whereby the traverse time of each of the chambers past a nozzle supported on the free end of the arm is uniform and constant.

An object of the present invention is to provide a fractioncollecting apparatus which achieves the requisite accuracy in an uncomplex, inexpensive structure. The present invention affords this object because the openings in the collecting disc are of uniform size and distribution thereby expediting and economizzing the economizing of the disc. Ready manufacture of the disc is important because it is most convenient, if not necessary, to have a plurality of such discs in analyzing a se ries of substances.

Contributing to the attainment of the foregoing object the present invention includes a supporting structure for the disc which assures-that each opening or chamber as it receives fluid does so at a constant and uniform time interval. The present object affords this advantageous mode of operation because the driving connection between the motor and the disc travels radially in exact correspondence with the inlet nozzle from the fractionating column.

A feature and advantage of the mode of operation described in the preceding paragraph is that a relatively inexpensive synchronous motor can be used to drive the disc.

Another feature and advantage of the invention is that because the collecting openings or chambers are arranged in a spiral path the disc inwhich the chambers are formed is compact for ease of transport and storage.

The foregoing together with other objects, features and advantages will be more apparent after referring to the following specification and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partially schematic perspective view of a fraction collecting apparatus of the present invention.

FIG. 2 is a plan view of a collecting disc embodying the present invention.

FIG. 3 is a top view of the driving apparatus with the disc removed to reveal various details of construction.

FIG. 4 is a cross-sectional view taken generally along line 44 of FIG. 3.

FIG. 4A is a fragmentary view of a portion of FIG. 4 at enlarged scale.

FIG. 4B is a fragmentary view showing at enlarged scale another detail of FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring more particularly to the drawings reference numeral 12 indicates the base on which the balance of the elements are supported. Centrally of the base there is supported for free rotation relative the base a capstan member 14 which has at the upper end thereof a non-circular portion exemplified in FIG. 48 by a cross pin 16. Base 12 supports a disc-shaped body 18 the body having a central opening 20 with diametrically opposite excisions 22 which are complemental to the protruding ends of cross pin 16 so as to form a driving connection between the disc and the capstan when the disc is in place as shown in FIGS. 1 and 4.

As seen most clearly in FIG. 4, disc 18 has an upper planar surface 24 and a lower planar surface 26 which is parallel to the upper surface. Formed in body 18 in communication with surface 24 is a plurality of openings or chambers 28. Each chamber 28 is of uniform diameter and depth and can be conveniently formed by drilling. As shown in FIG. 4A the portion of opening 28 adjacent upper surface 24 is excised or chamfered at 30 to form a diverging entrance portion for chamber 28.

As seen in FIG. 2 openings 28 are arranged in a spiral pattern around center hole 20. Diverging portions 30 are sufficiently deep that a knife edge 32 is formed between each adjacent pair of openings 28. Thus a liquid drop falling midway between two adjacent openings 28 will be evenly distributed between the openings because of the presence of knife edge 32.

Openings 28 are arranged on a spiral path that extends from an outermost opening 28a to an innermost opening 28b. As will appear in more detail hereinafter as the disc is rotated the structure that carries the liquid output of a fractionating column moves radially inward so as to maintain constant alignment with the spiral path on which openings 28 are disposed.

With reference to FIG. 3 base 12 supports a carriage 34 on a path that extends radially of capstan 14. Base 12 is excised at 36 to accommodate carriage 34 and its accoutrement. Spanning excision 36 are a pair of parallelly spaced rigid rods 38 and 40. Carriage 34 includes spaced apart support plates 42 and 44 extending between which are tubular bushings 46 and 48 that support the carriage for sliding movement along rods 38 and 40. Carriage 34 is resiliently biased toward one extreme of its radial path of travel (the outward extreme in the embodiment shown in the drawings) by compression springs 50 and 52 which circumscribe rods 38 and 40, respectively.

Extending between support plates 42 and 44 is a shaft which carries a drive wheel 54. Drive wheel 54 preferably has a peripheral groove in which is mounted a rubber O-ring 56 which forms a high friction surface to afford a driving connection between the drive wheel and lower surface 26 of disc 18. As seen in FIG. 4A there is mounted'concentric and rigid with the shaft on which drive wheel 54 is mounted a plurality of gears 58a, 58b, 58c, 58d and 58s.

Also spanning support plates 42 and 44 is a driven shaft 60 on which is supported a set of gears 62 which corresond to or complement gears'58. A counter-shaft 64 is also provided in spanning relation of the space between support plates 42 and 44; the counter-shaft carries an intermediate gear 66 the axial position of which is established by the adjacent gears. Support plates 42 and 44 are formed with five pairs of aligned bearing holes for supporting counter-shaft 64 at radial distances from gears 58 and 62 such that intermediate gear 66 properly meshes at all axial positions on the counter-shaft. A knob 69 has a threaded connection with counter-shaft 64 so that the counter-shaft can be mounted in one of five pairs of holes in support plates 42 and 44 to afford meshing between intermediate gear 66 and gears 58 and 62. Thus loosening knob 69 permits intermediate gear to couple one of the individual gears 58 to one of the individual gears 62 on shaft 60 in order to change the gear ratio and relative speed therebetween. Shaft 60 is driven by a motor 70 which is a synchronous or like constant speed motor so that drive wheel 54 revolves at a constant speed, the particular speed being determined by the position of intermediate gear 66 along counter-shaft 64. In any event upon connection of electric power to motor 70 drive wheel 54 rotates at a constant speed so that the tangential speed of the portion of disc 18 that is in contact with the drive wheel is correspondingly constant. Rotatively supported on base .12 at the same vertical level as drive wheel 54 arev idler rollers 72 and 74 which in conjunction with the drive wheel support disc 18 for free rotation on the base. Such rotation, caused by drive wheel 54 causes capstan 14 to rotate. Capstan 14 is journalled for rotation in base 12 at 76; intermediate the journal and cross pin 16 is a smooth spool-like portion 78 at which portion a hole 80 is drilled through the capstan. Secured in hole 80 is one end ofa flexible tension member 82 the opposite end of which is fastened to base 12 at 84. The medial portion of flexible tension member 82 is trained around a sheave 86 which is rotatively supported on a bracket 88 which is fixed to carriage 34 by a fastener 90. It will thus be seen that as capstan 14 is rotated flexible tension member 82 is wound on spool-like portion 78 to move sheave 86 and carriage 34 in a rightwardor inner direction as viewed in the drawings. By'proper selection of the diameter of spoollike portion in reference to the configuration of the spiral path of openings 28, friction wheel 54 follows the spiral path so that the tangential speed of the spiral path opposite the drive wheel is constant so long as the speed of rotation of the drive wheel is constant.

Rigidly supported to carriage 34 is an arm 92 which has an upwardly extending portion 94 from the upper end of which is an inward portion 96. Portion 96 of the arm overlays the area of disc 12 in vertical alignment above drive wheel 54 so that the inner portion follows a corresponding spiral path. Formed in the outer end of arm 9.6 is an elongate 'slot 97 in which is mounted a fluid nozzle 98. Fluid nozzle 98 is retained in slot 97 by means of a nut 99 so that the position of the nozzle can be adjusted for precise alignment with the spiral path along which openings 28 are disposed. A U-shaped bar 100 is mounted rigidly to base 12 so as to avoid obstruction of full radial movement of arm 92 and carriage 34 to which it is fixed.

In operation the apparatus of the invention is connected via an outlet tube T to a fractionating column C, or like equipment, that produces a flow of constituents on a time related basis. Accordingly, the output liquid from the fractionating column will enter nozzle 98 and drip through the central passage thereof. Before a disc 18 is installed on the apparatus springs 50 and 52 urge carriage 34 to its outermost position. Disc 18 is then installed by engaging the walls of opening 20 with capstan l4 and excisions 22 with the ends of cross pin 16. At the start position, drive wheel 54 will be in substantial alignment with opening 28a in disc 18. Nozzle 98 can be adjusted in slot 97 so that the nozzle lies directly over the opening and lies directly over the drive wheel. As liquid exits fractionating column C and passes through tube T to nozzle 98 power is supplied to motor 70 which through the gear train composed of gears 62, 66 and 58 rotates drive wheel 54. Because of the friction contact between the periphery of the drive wheel and surface 26 of disc 18, the disc rotates and causes each opening to traverse nozzle 98. Rotation of disc 18 causes corresponding rotation of capstan 14 which in turn causes flexible tension member 82 to be wound onto spool-like portion 78. The consequence of winding flexible tension member 82 onto the capstan is that carriage 34 is moved radially inward. The path on which flexible tension member 82 is trained and the diameter 'of spool-like portion 78 of the capstan are chosen in relation to the spiral path on which openings 28 are disposed so that drive wheel 54 and nozzle 98 remain in vertical alignment with the openings. Thus the traverse time of each opening 28 beneath nozzle 98 is constant because the tangential speed of that region of disc 18 in alignment with the nozzle is constant. Thus the fluid collected in each and every opening or chamber 28 represents a constant or uniform time interval, a precondition for accurate analysis of the substance introduced to column C. Such time interval can be selected by appropriate positioning of intermediate gear 66 along shaft 64.

When collection is complete, i.e., when nozzle 98 reaches a position in vertical alignment over opening 28b, an actuator 102 of a microswitch 104 is contacted by a portion of carriage 34 (e.g., motor 70) and power to the motor is interrupted. Disc 18 is then removed for subsequent processing in accordance with conventional analysis techniques. On removal of the disc carriage 34 moves outwardly in response to the energy stored in springs 50 and 52, thus readying the apparatus for another fraction collecting procedure.

Because each and every opening 28 in disc 18 is identical in size and shape, fabrication costs of the disc are materially reduced. Accordingly, it is feasible to provide a plurality of discs 18 with each base assembly 12 so that discs can be stored and subjected to other procedures while a different disc is in place on the apparatus. In one structure designed according to the invention, disc 18 is formed of nylon having a thickness of about one inch and a diameter of about inches, such exemplary disc having 180 openings or chambers 28. Each opening has a diameter of eleven thirtyseconds inches and a depth below surface 24 of about eleven-sixteenths inch plus the depth of the conical bottom surface corresponding to a drill tip. Diverging portions 30 are formed in such exemplary embodiment with an included angle of about 65. The diverging portions are formed to a depth sufficient to form knife edge 32 between pairs of adjacent openings 28.

An equivalent structure to disc 18 is a fabricated carrier for separate containers such as l0 mm test tubes. The equivalent structure is made ofsuitable plate material, such as aluminum, and has a planar lower surface for cooperation with drive wheel 54. Secured to the upper surface of the plate in a spiral path is a plurality of tubular members, or the like, into which the test tubes are inserted. Use of the equivalent structure proceeds as described hereinabove.

Thus it will be seen that the present invention provides a fraction collecting apparatus that achieves the requisite uniformity of time interval for each collection chamber in a straightforward uncomplex and relatively inexpensive fashion. Accordingly, improved accuracy at low cost is made possible by the present invention.

Although one embodiment has been shown and described, it will be obvious that other adaptations and modifications can be made without departing from the true spirit and scope of the invention What is claimed is:

1. In a fraction collector the combination comprising a body having a lower planar surface and a plurality of equi-size liquid receiving chambers having upward openings, said chambers being disposed in uniform spaced relation along a spiral path about a central point on said body, a base having means for mounting said body for rotation about said central point, a carriage and means on said base for constraining said carriage for movement on a radial path below said lower surface, a drive wheel mounted in said carriage forrotation about a radially disposed axis, said drive wheel having a periphery in contact with said lower body surface for establishing a frictional driving connection therebetween, means mounted in said carriage for rotatively driving said drive wheel at a substantially constant speed so as to impart to the portion of said body in contact with said drive wheel a correspondingly constant tangential speed, an arm having a first end fixed to said carriage and a second end overlying said upper surface in substantial vertical alignment with said drive wheel, means for moving said carriage along said radial path in a first radial direction in response to said drive wheel rotatively driving said body so that the second end of said arm traverses the spiral path of the chambers, and means for resiliently biasing said carriage along said radial path in a second direction opposite said first direction so that on disengagement of said lower body surface from said drive'wheel periphery, said biasing means moves said carriage in said second direction.

2. A fraction collector according to claim 1 wherein said carriage moving means comprises a capstan rotatively supported on said base in driven relation to said body mounting means, a flexible tension member having a first end secured to said capstan so that said tension member is wound around said capstan upon rota tion thereof, said flexible tension member having a por tion remote from said first end, and means for operatively connecting said remote portion to said carriage so that said carriage is moved along said radial path in a given direction in response to rotation of said capstan.

3. A fraction collector according to claim 2 wherein said operatively connecting means comprises a sheave journalled for rotation on said carriage, said flexible tension member being engaged around said sheave, said flexible tension member having a second end opposite said first end, and means for fixing said second end to said base.

4. In a fraction collector the combination comprising a base, a capstan journalled for rotation on said base about a generally vertical axis, a carriage and means on said base for supporting said carriage for movement along a path radially of said capstan, a flexible tension member having a first end secured to said capstan so that said tension member is wound around said capstan upon rotation thereof, said flexible tension member having a portion remote from said first end, means for operatively connecting said remote portion to said carriage so that said carriage is drawn along said path in a given direction in response to rotation of said capstan, means for resiliently biasing said carriage in a direction opposite said given direction, a friction wheel supported on said carriage for rotation about a radial axis so that the periphery thereof projects above said base, means carried in said carriage for driving said wheel at a substantially constant speed, a rigid impervious disc having upper and lower mutually parallel planar surfaces and defining a central opening for affording a driving connection with the said capstan, the lower surface of said disc resting on said friction wheel for driven interconnection therewith so that in response to rotation of said friction wheel by said driving means said disc rotates said capstan which in turn winds said flexible tension member therearound so as to constrain said wheel for movement in a spiral path 8 surface, said disc defining a plurality of equi-si zed openings uniformly spaced along last said path, and means for mounting an outlet nozzle of a fractionating column to the second end of said arm. 

1. In a fraction collector the combination comprising a body having a lower planar surface and a plurality of equi-size liquid receiving chambers having upward openings, said chambers being disposed in uniform spaced relation along a spiral path about a central point on said body, a base having means for mounting said body for rotation about said central point, a carriage and means on said base for constraining said carriage for movement on a radial path below said lower surface, a drive wheel mounted in said carriage for rotation about a radially disposed axis, said drive wheel having a periphery in contact with said lower body surface for establishing a frictional driving connection therebetween, means mounted in said carriage for rotatively driving said drive wheel at a substantially constant speed so as to impart to the portion of said body in contact with said drive wheel a correspondingly constant tangential speed, an arm having a first end fixed to said carriage and a second end overlying said upper surface in substantial vertical alignment with said drive wheel, means for moving said carriage along said radial path in a first radial direction in response to said drive wheel rotatively driving said body so that the second end of said arm traverses the spiral path of the chambers, and means for resiliently biasing said carriage along said radial path in a second direction opposite said first direction so that on disengagement of said lower body surface from said drive wheel periphery, said biasing means moves said carriage in said second direction.
 2. A fraction collector according to claim 1 wherein said carriage moving means comprises a capstan rotatively supported on said base in driven relation to said body mounting means, a flexible tension member having a first end secured to said capstan so tHat said tension member is wound around said capstan upon rotation thereof, said flexible tension member having a portion remote from said first end, and means for operatively connecting said remote portion to said carriage so that said carriage is moved along said radial path in a given direction in response to rotation of said capstan.
 3. A fraction collector according to claim 2 wherein said operatively connecting means comprises a sheave journalled for rotation on said carriage, said flexible tension member being engaged around said sheave, said flexible tension member having a second end opposite said first end, and means for fixing said second end to said base.
 4. In a fraction collector the combination comprising a base, a capstan journalled for rotation on said base about a generally vertical axis, a carriage and means on said base for supporting said carriage for movement along a path radially of said capstan, a flexible tension member having a first end secured to said capstan so that said tension member is wound around said capstan upon rotation thereof, said flexible tension member having a portion remote from said first end, means for operatively connecting said remote portion to said carriage so that said carriage is drawn along said path in a given direction in response to rotation of said capstan, means for resiliently biasing said carriage in a direction opposite said given direction, a friction wheel supported on said carriage for rotation about a radial axis so that the periphery thereof projects above said base, means carried in said carriage for driving said wheel at a substantially constant speed, a rigid impervious disc having upper and lower mutually parallel planar surfaces and defining a central opening for affording a driving connection with the said capstan, the lower surface of said disc resting on said friction wheel for driven interconnection therewith so that in response to rotation of said friction wheel by said driving means said disc rotates said capstan which in turn winds said flexible tension member therearound so as to constrain said wheel for movement in a spiral path upon the lower surface of said disc, a rigid arm having a fist end fixed to said carriage and a second end overlying the upper surface of said disc in substantial vertical alignment with said friction wheel so that said second end traverses a similar spiral path over said upper surface, said disc defining a plurality of equi-sized openings uniformly spaced along last said path, and means for mounting an outlet nozzle of a fractionating column to the second end of said arm. 